Device for dispensing a heated fluid

ABSTRACT

A heat exchanger assembly and a hot water appliance including a heat exchanger and a burner assembly. The heat exchanger assembly includes a head portion including a water inlet for receiving water at a first temperature, a water outlet for outputting water at a second temperature higher than the first temperature, and a gas inlet port for receiving combustion gases. The heat exchanger assembly also includes a tube bundle including a plurality of combustion chamber tubes positioned about the gas inlet port, and a plurality of condensation chamber tubes positioned adjacent and parallel to the plurality of combustion chamber tubes. Each combustion chamber tube has a first surface shape and each condensation chamber tube has a second surface shape that is different than the first surface shape.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional Patent Application Ser. No. 62/286,596, filed Jan. 25, 2016, the disclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

The invention relates generally to heating devices, and more particularly, to a device for heating and dispensing fluids.

It is known to heat tap water in various ways. It is known to have a supply of tap water, wherein the tap water is heated directly by means of a separate exchanger with its own heat sources. This is connected to a supply tank. It is known to suction fluid out of the supply, usually from a low point in the supply, and to transport this to the heat exchanger. The pressure conduit carries the fluid back into the supply, often also at a low point. Owing to thermal action, the hot water will hereby rise upward from the bottom until the whole supply has the desired temperature. The external heating is switched on when a control device determines by temperature measurement that the temperature of the heated fluid in the supply is too low. The temperature detecting means can be placed in the supply, or is for instance placed downstream of the heat exchanger.

In a commercial or industrial setting, the heat exchanger may be included within a closed loop heating boiler. The boiler receives water returning from a load, such as in a building or process being heated, will heat the water, and will return the water supplying the heat to the load to effectuate a constantly recirculating loop.

SUMMARY

In one embodiment, a heat exchanger assembly includes a head portion including a water inlet for receiving water at a first temperature, a water outlet for outputting water at a second temperature higher than the first temperature, and a gas inlet port for receiving combustion gases. The heat exchanger assembly also includes a tube bundle including a plurality of combustion chamber tubes positioned about the gas inlet port and a plurality of condensation chamber tubes positioned adjacent and parallel to the plurality of combustion chamber tubes. Each combustion chamber tube has a first surface shape and each condensation chamber tube has a second surface shape that is different than the first surface shape.

In another embodiment, a hot water appliance includes a burner assembly configured to generate combustion gases, and a heat exchanger assembly configured to receive the combustion gases from the burner assembly. The heat exchanger includes a head portion including a water inlet for receiving water at a first temperature, a water outlet for outputting water at a second temperature higher than the first temperature, and a gas inlet port for receiving the combustion gases. The heat exchanger assembly also includes a tube bundle including a plurality of combustion chamber tubes positioned about the gas inlet port and a plurality of condensation chamber tubes positioned adjacent and parallel to the plurality of combustion chamber tubes. Each combustion chamber tube has a first surface shape and each condensation chamber tube has a second surface shape that is different than the first surface shape.

BRIEF DESCRIPTION OF THE DRAWINGS

Advantages of the present disclosure will be readily appreciated, as the same becomes better understood by reference to the following detailed description, when considered in connection with the accompanying drawings. Non-limiting and non-exhaustive embodiments of the present disclosure are described with reference to the following figures, wherein like numerals refer to like parts throughout the various views unless otherwise specified.

FIG. 1A is a perspective view of an exemplary hot water appliance.

FIG. 1B is a perspective view of an exemplary heat exchanger assembly that may be positioned within the hot water appliance shown in FIG. 1A.

FIG. 1C is a perspective view of an exemplary heat exchanger that may be included within the heat exchanger assembly shown in FIG. 1B.

FIG. 2 is a perspective view of the heat exchanger assembly shown in FIG. 1B.

FIG. 3 is an exploded view of the heat exchanger assembly shown in FIG. 2.

FIG. 4 is a sectional view of a head portion of the heat exchanger assembly shown in FIG. 2 taken along line A-A.

FIG. 5 is an exploded sectional view of the head portion of the heat exchanger assembly shown in FIG. 2 taken along line A-A.

FIG. 6 is a section view of a bottom portion of the heat exchanger assembly shown in FIG. 2 taken along line B-B.

FIG. 7 is a perspective view of the heat exchanger shown in FIG. 1C.

FIG. 8 is a top view of the tube sheet shown in FIG. 7.

FIG. 9 is a perspective view of a portion of the heat exchanger shown in FIG. 1C.

FIG. 10 is a cut-away view of a bottom section of the heat exchanger shown in FIG. 1C.

FIG. 11 is another cut-away view of the heat exchanger shown in FIG. 1C.

FIG. 12 is a perspective view of a portion of a plurality of combustion gas diverter baffles shown in FIG. 7.

FIG. 13 is a cross-sectional view of a portion of a plurality of combustion chamber tubes and condensation chamber tubes shown in FIG. 7.

FIG. 14 is a perspective view of a portion of the condensation chamber tubes shown in FIG. 7.

DETAILED DESCRIPTION

Embodiments disclosed herein describe a hot water appliance, such as a water heater or a boiler. The hot water appliance includes a heat exchanger assembly that includes a heat exchanger. The heat exchanger assembly and heat exchanger are fully serviceable by maintenance personnel. For example, a head portion and a bottom portion may be removed from a body portion of the heat exchanger assembly in the event a component therein fails or degrades in performance. The body portion encloses a tube bundle. The body portion is formed of removable sealing panels that are bolted or otherwise removably coupled together and to the head and body portions. Removable fiber boards are also placed on an interior of the body portion to reflect heat into a combustion chamber of the heat exchanger. Various gaskets and sealing flanges are also used to seal the chambers of the heat exchanger while also enabling the various components to be removed and/or serviced by maintenance personnel.

Some heat exchangers on the market have removable heads, but they may not have the ability to have all individual components be replaceable and serviceable as the present application enables. By being fully serviceable and replaceable, the heat exchanger assembly described herein may significantly increase the life of the installed appliance, while avoiding the major expense of replacing the entire heat exchanger when a significant component (e.g., a tube or heating element) fails or springs a leak.

FIG. 1A is a perspective view of an exemplary hot water appliance 100. FIG. 1B is a perspective view of a heat exchanger assembly 102 that is positioned within hot water appliance 100. FIG. 1C is a perspective view of an exemplary heat exchanger 104 that may be included within heat exchanger assembly 102.

In one embodiment, hot water appliance 100 is a water heater or a boiler usable in residential or industrial settings. Hot water appliance 100 may include, for example, heat exchanger assembly 102 and a burner assembly 106. Burner assembly 106 may include a gas valve 108 for enabling or disabling a flow of a fuel, such as natural gas or propane, for example, received through a gas inlet 110, an air inlet 112 for receiving air into burner assembly 106, and an igniter 114 for igniting the fuel and air. A blower 116 blows combustion gases resulting from the ignited fuel into heat exchanger assembly 102. A control board 118 controls the operation of hot water appliance 100 including the operation of burner assembly 106. An appliance control display 120 may display operational data relating to the operation of hot water appliance 100 and/or may enable an operator to input commands that are then transmitted to control board 118 for controlling hot water appliance 100.

During operation, water enters hot water appliance 100 at a first temperature through a water inlet 122, is heated within heat exchanger assembly 102 by burner assembly 106, and exits through a water outlet 124 at a second, higher temperature. Combustion gases generated by burner assembly 106 may exit hot water appliance 100 through an exhaust port 126.

In one embodiment shown in FIGS. 1A and 1B, heat exchanger assembly 102 includes a plurality of feet 128 that are positioned to impart a tilt or angle of inclination to heat exchanger assembly 102. For example, in one embodiment, 4 feet 128 are included, with 2 feet 128 positioned toward a front portion 130 of heat exchanger assembly 102 having a higher height than 2 feet 128 positioned toward a back portion 132 of heat exchanger assembly 102. In such a manner, condensate that may form during the operation of heat exchanger assembly 102 may be directed by gravity toward a condensate drain 134 of heat exchanger assembly 102. In one embodiment, feet 128 impart an angle of inclination of about 2.5 degrees with respect to a floor of hot water appliance. Alternatively, feet 128 may impart any other suitable angle of inclination to heat exchanger assembly 102.

FIG. 2 is a perspective view of heat exchanger assembly 102. In one embodiment, heat exchanger assembly 102 includes a head portion 202 including water inlet 122, water outlet 124, and a burner insertion port 204. Heat exchanger assembly 102 also includes a body portion 206 coupled to head portion 202 and a bottom portion 208 coupled to body portion 206.

Head portion 202 may be manufactured from stainless steel or another suitable metal or alloy. Head portion 202 may also include a plurality of air vents 210 that enable air to be vented from one or more internal chambers of heat exchanger assembly 102.

Burner insertion port 204 is a substantially circular hole that is sized and shaped to receive combustion gases generated from a combustion process of burner assembly 106. Accordingly, burner insertion port 204 operates as a gas inlet port for heat exchanger assembly 102. For example, in one embodiment, burner assembly 106 is coupled to head portion 202 so that an exhaust port (not shown) of burner assembly 106 is inserted within, or is connected to, burner insertion port 204. As burner assembly 106 combusts fuel, such as propane, natural gas, or other suitable fuel, the resulting gases exit burner assembly 106 and enter burner insertion port 204. The combustion gases then flow through heat exchanger 104 as described more fully herein.

Body portion 206 includes a plurality of removable side sealing panels 212, a front sealing panel 214, and a back sealing panel 216 (shown in FIG. 7) for sealing one or more internal chambers of body portion 206. For example, in one embodiment, side sealing panels 212, front sealing panel 214, and back sealing panel 216 sealingly enclose a combustion chamber and a condensation chamber (not shown in FIG. 2) of heat exchanger assembly 102.

In one embodiment, heat exchanger assembly 102 is fully serviceable by maintenance personnel. For example, front sealing panel 214 and side sealing panels 212 may be removable to enable maintenance personnel to access internal components and chambers of heat exchanger assembly 102. In one embodiment, front sealing panel 214 and side sealing panels 212 are removably coupled to each other, to head portion 202, and to bottom portion 208 by bolts or other removable fasteners. In addition, head portion 202 and bottom portion 208 may be removably coupled to body portion 206 by a plurality of bolts or other suitable fasteners.

FIG. 3 is an exploded view of heat exchanger assembly 102. In the example shown in FIG. 3, heat exchanger assembly 102 includes head portion 202, heat exchanger 104, front sealing panel 214, side sealing panels 212, and bottom portion 208.

In addition, one or more fiber boards 302 are coupled to front sealing panel 214 and side sealing panels 212. Fiber boards 302 are provided to reflect heat emanating from the combustion chamber back into the combustion chamber, therefore, substantially preventing heat from escaping the combustion chamber through the sealing panels. In one embodiment, fiber boards 302 are manufactured from a flexible ceramic material and may be formed in boards between ⅛ of an inch to 1 inch thick. Alternatively, fiber boards may be manufactured from any suitable material and may be any suitable thickness.

As shown in FIG. 3, heat exchanger 104 includes a top tube sheet 304 to which head portion 202 may be removable coupled. To facilitate sealing heat exchanger 104 and body portion 206, top tube sheet 304 includes one or more tube sheet gaskets 306 positioned along a perimeter 308 of top tube sheet 304. In addition, a combustion gas inlet port 310 is defined in top tube sheet 304 and is coupled to burner insertion port 204 such that combustion gas inlet port 310 and burner insertion port 204 are in flow communication with each other. In other words, combustion gases flowing through burner insertion port 204 from burner assembly 106 enter heat exchanger 104 through combustion gas inlet port 310. The combustion gases are then dispersed through heat exchanger 104 as described herein. A sealing gasket 312, such as an O-ring gasket, is coupled to a top portion of combustion gas inlet port 310 to facilitate sealingly coupling head portion 202 to top tube sheet 304.

A tube bundle 314 is coupled to top tube sheet 304 and to bottom portion 208. In one embodiment, tube bundle 314, top tube sheet 304, head portion 202, bottom portion 208, and side sealing panels 212 are manufactured from stainless steel or another suitable metal or alloy.

FIG. 4 is a sectional view of head portion 202 taken along line A-A of FIG. 2. FIG. 5 is an exploded sectional view of head portion 202 taken along line A-A of FIG. 2. In one embodiment, head portion 202 includes a plurality of water diverter baffles, such as a first top water diverter baffle 402, a second top water diverter baffle 404, and a third top water diverter baffle 406. The diverter baffles are used to form various water chambers and to divert or direct water flow through predefined groups of water tubes. More specifically, each water chamber is open in a direction facing the tubes of tube bundle 314 such that as water fills each water chamber, the water is forced or directed into respective tubes facing the water chamber.

A first top water chamber 408 is formed between a back end 410 of head portion 202 (i.e., through which water inlet 122 and water outlet 124 are coupled) and first top water diverter baffle 402. As shown in FIGS. 7 and 8, water enters first top water chamber 408 from water inlet 122 and is directed into a first group of tubes as described below. A second top water chamber 412 is formed between first top water diverter baffle 402 and second top water diverter baffle 404. In one embodiment, water fills second top water chamber 412 from a second group of tubes and is directed into a third group of tubes. A third top water chamber 414 is formed between second top water diverter baffle 404 and third top water diverter baffle 406. In one embodiment, water fills third top water chamber 414 from a fourth group of tubes and is directed into a fifth group of tubes. A fourth top water chamber 416 is formed between third top water diverter baffle 406 and a front end 418 of head portion 202. In one embodiment, water fills fourth top water chamber 416 from a sixth group of tubes and is directed out of head portion 202 and heat exchanger assembly 102 through water outlet 124. Alternatively, any suitable number of water chambers, water diverter baffles, and tube groupings may be used as desired.

Head portion 202 includes a sealing flange 420 on a bottom portion of burner insertion port 204. Sealing flange 420 may be removably coupled to sealing gasket 312 of combustion gas inlet port 310 as described above with reference to FIG. 3 to sealingly couple head portion 202 to top tube sheet 304 (i.e., to sealingly couple burner insertion port 204 to combustion gas inlet port 310.

FIG. 6 is a sectional view of bottom portion 208 taken along line B-B of FIG. 2. In one embodiment, bottom portion 208 includes a plurality of water diverter baffles, such as a first bottom water diverter baffle 602 and a second bottom water diverter baffle 604. The diverter baffles are used to form various water chambers and to divert or direct water flow through predefined groups of water tubes. More specifically, each water chamber is open in a direction facing the tubes of tube bundle 314 such that as water fills each water chamber, the water is forced or directed into respective tubes facing the water chamber.

A first bottom water chamber 606 is formed between a back end 608 of bottom portion 208 and first bottom water diverter baffle 602. As shown in FIGS. 7 and 8, water enters first bottom water chamber 606 from the first group of tubes and is directed into the second group of tubes as described below. A second bottom water chamber 610 is formed between first bottom water diverter baffle 602 and second bottom water diverter baffle 604. In one embodiment, water fills second bottom water chamber 610 from the third group of tubes and is directed into the fourth group of tubes. A third bottom water chamber 612 is formed between second bottom water diverter baffle 604 and a front end 614 of bottom portion 208. In one embodiment, water fills third bottom water chamber 612 from a fifth group of tubes and is directed into the sixth group of tubes. Alternatively, any suitable number of water chambers, water diverter baffles, and tube groupings may be used as desired.

Head portion 202 includes sealing flange 420 on a bottom portion of burner insertion port 204. Sealing flange 420 may be removably coupled to sealing gasket 312 of combustion gas inlet port 310 as described above with reference to FIG. 3 to sealingly couple head portion 202 to top tube sheet 304 (i.e., to sealingly couple burner insertion port 204 to combustion gas inlet port 310.

In one embodiment, a drain 616 is formed in a bottom wall 618 of bottom portion 208. Drain 616 may be used to drain water or other fluids from heat exchanger assembly 102 during maintenance or similar activities.

FIG. 7 is a perspective view of heat exchanger 104 including top tube sheet 304 and tube bundle 314. FIG. 8 is a top view of top tube sheet 304.

In one embodiment, tube bundle 314 includes a plurality of combustion chamber tubes 702 and a plurality of condensation chamber tubes 704 that are each configured to channel water through heat exchanger 104. Each tube may be manufactured from stainless steel or another suitable metal or alloy.

As shown in FIGS. 7 and 8, combustion chamber tubes 702 may be arranged in a square formation around combustion gas inlet port 310. Alternatively, combustion chamber tubes 702 may be arranged in another suitable shape, such as a circle, an octagon, or the like. Accordingly, combustion chamber tubes 702 define a combustion chamber (not shown in FIG. 7 or 8) into which combustion gases flow from combustion gas inlet port 310. A plurality of combustion gas diverter baffles 706 may be positioned within the condensation chamber and/or the combustion chamber to direct the combustion gases through the chambers and across the tubes of each chamber in an efficient manner as described more fully herein.

Condensation chamber tubes 704 may be arranged in one or more groups and define a condensation chamber (not shown in FIG. 7 or 8) adjacent to the combustion chamber. It should be recognized that the combustion chamber and the condensation chamber are in flow communication with each other such that combustion gases within the combustion chamber flow into the condensation chamber. As the combustion gases flow over combustion chamber tubes 702 and condensation chamber tubes 704, heat from the combustion gases is transferred to the respective tubes and the water within the tubes is heated.

Condensation chamber tubes 704 and combustion chamber tubes 702 may be arranged in one or more groups of tubes, such as a first group of tubes 708, a second group of tubes 710, a third group of tubes 712, a fourth group of tubes 714, a fifth group of tubes 716, and a sixth group of tubes 718. Alternatively, condensation chamber tubes 704 and/or combustion chamber tubes 702 may be arranged in any suitable number of groups.

In the example shown in FIG. 8, first group 708, second group 710, third group 712, and fourth group 714 of tubes are condensation chamber tubes 704, while fifth group 716 and sixth group 718 of tubes are combustion chamber tubes 702. Each group of tubes may be identified as a “pass” which signifies a flow direction either from head portion 202 to bottom portion 208 or from bottom portion 208 to head portion 202. For example, first group of tubes 708 may direct water from head portion 202 to bottom portion 208 in a first pass, second group of tubes 710 may direct water from bottom portion 208 to head portion 202 in a second pass, third group of tubes 712 may direct water from head portion 202 to bottom portion 208 again in a third pass, and fourth group of tubes 714 may direct water from bottom portion 208 back to head portion 202 in a fourth pass. Likewise, fifth group of tubes 716 may direct water from head portion 202 down to bottom portion 208 in a fifth pass, and sixth group of tubes 718 may direct water back from bottom portion 208 to head portion 202 in a sixth pass. Alternatively, the number of groups and passes may be modified as desired in other embodiments.

More specifically, as shown in FIG. 8, first group of tubes 708 is in flow communication with first top water chamber 408 (shown in FIG. 4) such that water entering first top water chamber 408 is directed by first top water diverter baffle 402 through first group of tubes 708 and into first bottom water chamber 606 (shown in FIG. 6). First bottom water diverter baffle 602 then directs the water from first bottom water chamber 606 through second group of tubes 710 into second top water chamber 412. Second top water diverter baffle 404 directs the water from second top water chamber 412 through third group of tubes 712 into second bottom water chamber 610. Second bottom water diverter baffle 604 directs the water through fourth group of tubes 714 into third top water chamber 414. Third top water diverter baffle 406 directs the water through fifth group of tubes 716 into third bottom water chamber 612. From third bottom water chamber 612, the water is directed through sixth group of tubes 718 into fourth top water chamber 416, after which the water exits through water outlet 124. As the water travels through each group of tubes, the water is progressively heated by the combustion gases flowing through the condensation chamber and the combustion chamber.

While FIGS. 7 and 8 illustrate each group of tubes having two rows of tubes having a total of 21 tubes for each group, it should be recognized that any suitable number of tubes and rows of tubes may be used for each group of tubes in the condensation chamber. Likewise, any suitable number of tubes may be used in the combustion chamber (i.e., for combustion chamber tubes 702).

In addition, heat exchanger 104 may include a bottom tube sheet 720 that is coupled to tube bundle 314 and bottom portion 208. As described more fully herein, a plurality of sealing flanges and gaskets may be used to sealingly couple side sealing panels 212, front sealing panel 214, and/or back sealing panel 216 to each other and/or to bottom tube sheet 720.

FIG. 9 is a perspective view of a portion of heat exchanger 104 and bottom tube sheet 720. More specifically, FIG. 9 illustrates a portion of a sealing flange 902 and gasket 904 that may be used to sealingly couple front sealing panel 212, side sealing panels 214, and/or back sealing panel 216 to each other and/or to bottom tube sheet 720. In one embodiment, a corner seal assembly 906 seals a corner or an intersection of the panels, such as an intersection of front sealing panel 214 with each side sealing panel 212. Panel sealing flanges 902 have one or more threaded holes 908 for removably coupling flanges 902 to the panels, for example.

FIG. 10 is a cut-away view of a bottom section of heat exchanger 104. FIG. 11 is another cut-away view of heat exchanger 104. FIG. 12 is a perspective view of a portion of combustion gas diverter baffles 706.

Referring to FIG. 10, a combustion chamber 1002 is defined within an area surrounded by combustion chamber tubes 702. A condensation chamber 1004 is defined adjacent to combustion chamber 1002. Condensation chamber tubes 704 are positioned within condensation chamber 1004, and are substantially parallel to combustion chamber tubes 702.

An exhaust port 126 is defined in an end plate 1006 of heat exchanger 104 to exhaust combustion gases out of condensation chamber 1004. In addition, a condensate drain 134 is positioned at the bottom of condensation chamber 1004 and extends through end plate 1006 to drain condensate that forms during operation of heat exchanger assembly 102. As described above, heat exchanger assembly 102 is tilted or inclined by feet 128 of heat exchanger assembly 102 to cause the condensate to flow away from combustion chamber 1002 towards and through condensate drain 134 by the force of gravity.

As shown in FIG. 10, a plurality of combustion gas diverter baffles 706 are positioned within condensation chamber 1004 to direct the flow of combustion gases from combustion chamber 1002 through condensation chamber 1004. In one embodiment, combustion gas diverter baffles 706 include a first gas diverter baffle 1008, a second gas diverter baffle 1010, a third gas diverter baffle 1012, and a fourth gas diverter baffle 1014. First gas diverter baffle 1008 may, in one embodiment, separate combustion chamber 1002 from condensation chamber 1004.

As shown in FIG. 11, each combustion gas diverter baffle 706 has a gas aperture 1016 defined therein that is alternatingly positioned at a top or a bottom of each baffle. For example, in one embodiment, a first gas aperture 1018 is defined in a bottom of first gas diverter baffle 1008, a second gas aperture 1020 is defined in a top of second gas diverter baffle 1010, a third gas aperture 1022 is defined in a bottom of third gas diverter baffle 1012, and a fourth gas aperture 1024 is defined in a top of fourth gas diverter baffle 1014. The alternating positions of gas apertures 1016 causes the combustion gases to flow substantially uniformly over condensation chamber tubes 704 to heat the water therein in a substantially uniform manner.

As shown in FIG. 12, each combustion gas diverter baffle 706 also enables condensate to flow along the bottom of condensation chamber 1004 (i.e., along bottom tube sheet 720) towards and through condensate drain 134 to exit heat exchanger assembly 102. For combustion gas diverter baffles 716 having a gas aperture 1016 at a top portion therein, a separate drain aperture 1026 is defined in the baffle or between the baffle and bottom tube sheet 720. For combustion gas diverter baffles 706 having a gas aperture 1016 at a bottom portion therein, the condensate can flow through gas aperture 1016 normally without any additional apertures being defined. To enable the combustion gases to flow through gas apertures 1016, rather than through drain apertures 1026, drain apertures 1026 are preferably formed with a much smaller height than a height of gas apertures 1016. For example, in one embodiment, each drain aperture 1026 is about ⅛ of an inch in height, and each gas aperture 1016 is about 3 inches in height. Alternatively, any suitable height may be used for drain apertures 1026 and gas apertures 1016.

FIG. 13 is a cross-sectional view of a portion of combustion chamber tubes 702 and condensation chamber tubes 704 within heat exchanger 104. As shown in FIG. 13, each combustion chamber tube 702 has a diameter 1302 that may be different than a diameter 1304 of each condensation chamber tube 704. For example, in one embodiment, each combustion chamber tube 702 has a diameter 1302 of about 0.51 inches while each condensation chamber tube 704 has a diameter 1304 of about 0.582 inches. By reducing the diameter of combustion chamber tubes 702 as compared to the diameter of condensation chamber tubes 704, a tube velocity of water flowing through combustion chamber tubes 702 may be increased as compared to a tube velocity of water flowing through condensation chamber tubes 704. Since combustion chamber tubes 702 are positioned within, or around, combustion chamber 1002 and are exposed to higher temperature combustion gases than are condensation chamber tubes 704, a higher turbulent flow number is achieved by the higher tube velocity of combustion chamber tubes 702.

A higher turbulent flow number may also be achieved by reducing the number of combustion chamber tubes 702 as compared to the number of condensation chamber tubes 704. For example, as shown in FIG. 8, each group of tubes of condensation chamber tubes 704 (i.e., first group 708, second group 710, third group 712, and fourth group 714) includes 21 tubes, while each group of tubes of combustion chamber tubes 702 (i.e., fifth group 716 and sixth group 718) includes only 19 tubes. Since the same amount of water is transferred from condensation chamber tubes 704 to combustion chamber tubes 702, the use of fewer combustion chamber tubes 702 causes the tube velocity of combustion chamber tubes 702 to be further increased as compared to the tube velocity of condensation chamber tubes 704. In such a manner, the efficiency of heat exchanger assembly 102 may be increased as compared to prior art systems.

FIG. 14 is a perspective view of a portion of condensation chamber tubes 704. As shown in FIG. 14, condensation chamber tubes 704 have an external surface shape that is characterized by alternating fins 1402 and grooves 1404. Fins 1402 and grooves 1404 may be formed in condensation chamber tubes 704, for example, by machining or otherwise etching grooves 1404 in an otherwise substantially smooth tube. In contrast, the external surface shape of combustion chamber tubes 702 is substantially smooth, similar to those shown in FIG. 10.

By creating fins 1402 and grooves 1404 in condensation chamber tubes 704, a surface area of each tube may be increased by about 27% as compared to a surface area of a substantially smooth tube (e.g., as compared to a surface area of combustion chamber tubes 702). Accordingly, the higher surface area of condensation chamber tubes 704 enables the tubes to contact the combustion gases more fully, resulting in an increased amount of heat transfer from the gases to condensation chamber tubes 704. The efficiency of heat exchanger assembly 102 may therefore be increased as compared to prior art systems.

The embodiments described herein should be viewed as illustrative rather than limiting. For example, while the embodiments described herein generally refer to a heat exchanger assembly that is usable in residential or industrial settings, it should be recognized that the heat exchanger assembly described herein may be used with any suitable appliance or system.

In addition, components of devices or systems described herein may be used in, and/or combined with, other devices or systems described herein unless otherwise specified. Likewise, the functionality of the systems and devices described herein may be used in, combined with, and/or incorporated into other systems and devices described herein unless otherwise specified. For example, two or more of the systems or devices described herein may be combined together, and/or one or more of the systems or devices described herein may be split into two or more other systems or devices.

Unless otherwise specified, “a” or “an” means one or more of a referenced object or step. Furthermore, unless otherwise specified, each method described herein is not limited to the order in which the steps of each method are described or introduced. Rather, the steps may be rearranged in any suitable order, may be omitted, and/or may be combined with steps of other methods as desired. In addition, aspects or components of each embodiment and/or figure described herein may be omitted, or may be combined with, or modified to include, aspects or components of any other embodiment and/or figure unless otherwise specified.

Unless otherwise specified, the phrase “at least one of A and B” means one or more of A alone, one or more of B alone, or one or more of the combination of A and B.

This written description uses examples to describe embodiments of the disclosure, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 

What is claimed is:
 1. A heat exchanger assembly, comprising: a head portion comprising: a water inlet for receiving water at a first temperature; a water outlet for outputting water at a second temperature higher than the first temperature; and a gas inlet port for receiving combustion gases; and a tube bundle comprising: a plurality of combustion chamber tubes positioned about the gas inlet port, wherein each combustion chamber tube has a first surface shape; and a plurality of condensation chamber tubes positioned adjacent and parallel to the plurality of combustion chamber tubes, wherein each condensation chamber tube has a second surface shape that is different than the first surface shape.
 2. A heat exchanger assembly in accordance with claim 1, wherein each combustion chamber tube has a first internal diameter, and each condensation chamber tube has a second internal diameter that is different than the first internal diameter.
 3. A heat exchanger assembly in accordance with claim 1, wherein the head portion is removable from the heat exchanger assembly.
 4. A heat exchanger assembly in accordance with claim 3, further comprising a top tube sheet that is coupled to the tube bundle, and wherein the head portion is sealingly couplable with the top tube sheet by a gasket surrounding the combustion gas inlet port.
 5. A heat exchanger assembly in accordance with claim 1, further comprising a plurality of removable sealing panels enclosing the tube bundle.
 6. A heat exchanger assembly in accordance with claim 5, further comprising a plurality of removable fiber boards positioned between the plurality of sealing panels and the tube bundle.
 7. A heat exchanger assembly in accordance with claim 5, further comprising a seal assembly that sealingly couples a first sealing panel of the plurality of sealing panels to a second sealing panel of the plurality of sealing panels.
 8. A heat exchanger assembly in accordance with claim 7, further comprising a bottom tube sheet positioned below the plurality of sealing panels, and wherein the seal assembly further seals at least a portion of the first sealing panel and at least a portion of the second sealing panel with the bottom tube sheet.
 9. A heat exchanger assembly in accordance with claim 1, further comprising a body portion enclosing the tube bundle, and a bottom portion that is removably coupled to the body portion.
 10. A heat exchanger assembly in accordance with claim 1, wherein the first surface shape of each of the plurality of combustion chamber tubes is substantially smooth and the second surface shape of each of the plurality of condensation chamber tubes is characterized by alternating fins and grooves.
 11. A hot water appliance comprising: a burner assembly configured to generate combustion gases; and a heat exchanger assembly configured to receive the combustion gases from the burner assembly, the heat exchanger comprising: a head portion comprising: a water inlet for receiving water at a first temperature; a water outlet for outputting water at a second temperature higher than the first temperature; and a gas inlet port for receiving the combustion gases; and a tube bundle comprising: a plurality of combustion chamber tubes positioned about the gas inlet port, wherein each combustion chamber tube has a first surface shape; and a plurality of condensation chamber tubes positioned adjacent and parallel to the plurality of combustion chamber tubes, wherein each condensation chamber tube has a second surface shape that is different than the first surface shape.
 12. A hot water appliance in accordance with claim 11, wherein each combustion chamber tube has a first internal diameter, and each condensation chamber tube has a second internal diameter that is different than the first internal diameter.
 13. A hot water appliance in accordance with claim 11, wherein the head portion is removable from the heat exchanger assembly.
 14. A hot water appliance in accordance with claim 13, further comprising a top tube sheet that is coupled to the tube bundle, and wherein the head portion is sealingly couplable with the top tube sheet by a gasket surrounding the combustion gas inlet port.
 15. A hot water appliance in accordance with claim 11, further comprising a plurality of removable sealing panels enclosing the tube bundle.
 16. A hot water appliance in accordance with claim 15, further comprising a plurality of removable fiber boards positioned between the plurality of sealing panels and the tube bundle.
 17. A hot water appliance in accordance with claim 15, further comprising a seal assembly that sealingly couples a first sealing panel of the plurality of sealing panels to a second sealing panel of the plurality of sealing panels.
 18. A hot water appliance in accordance with claim 17, further comprising a bottom tube sheet positioned below the plurality of sealing panels, and wherein the seal assembly further seals at least a portion of the first sealing panel and at least a portion of the second sealing panel with the bottom tube sheet.
 19. A hot water appliance in accordance with claim 11, wherein the first surface shape of each of the plurality of combustion chamber tubes is substantially smooth and the second surface shape of each of the plurality of condensation chamber tubes is characterized by alternating fins and grooves.
 20. A hot water appliance in accordance with claim 11, further comprising a housing that encloses the burner assembly and the heat exchanger assembly, wherein the heat exchanger assembly includes a plurality of feet that tilt the heat exchanger with respect to a bottom surface of the housing. 